Train board



Oct. 3, 1933.

S. Y. MCGIFFERT ET AL TRAIN BOARD Filed Jan.

2 Sheets-Sheeft l INVENTOR.

www??? Oct. 3, 1933. 5 Y McGlFFERT Er AL 1,929,250

TRAIN BOARD Filed Jan. 23, 1932 2 Sheets-Sheet 2 A TTORNE Ys,

Patented Oct. 3, 1933 .TRAIN BOARD stephen Y. McGiffert, Fort siu, Okla., ana Hugh` P. Adams, Fort Sam Houston, Tex.

Application January 23, 1932, seial No. 588,356,

and in Germany October 2, ,1931 t 24 claims. (c1. sae-'12) We have filed application for Letters Patent hereon in Germany` on Gctober 2,Y 1931, tion Number M. 117,098 XI/72J.

' This inventionrelates to apparatus for training officers in the conduct 4of field artillery fire and represents an improvement upon previously known methods such as blackboard practice and previously known terrainboards. Itaims to provide apparatus which will reproduce on a minia- Vture scale but with a lifelike appearance and with mathematical accuracy the firing of an actual battery under real conditions.

This application is a continuation in part or our application Serial No. 345,717 for U. S. Letters Patent, led March 9, 1929, since issued as Patent by a person not acquainted lwith`V` the ballistics,v gunnery and the principles of eld artillery ring,

under the direction of a .student in such a manner that the student, who represents the commander of a battery, does not need to give'any attention to the operator other than preliminary instructions. Further aims are the provision of apparatus of this sort characterized by such size and'weight as to be portable, by' strength and simplicity of construction and reasonable cost of manufacture. Further aims and advantages of the invention Will appear as the description proceeds.- To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosednieans constituting, however, but one of various mechanical forrns in which the principles of the invention may be used.

In said annexed drawings:

Fig. 1 is a perspective viewof the assembled apparatus; Fig. 2 is a diagrammatic plan corresponding to Fig. 1 illustrating the arrangement oi the apparatus for useto represent axial ring; Fig. 3 is a front View showing the appearance of the apparatus to the student when arranged to represent lateral observation; Fig. 4 is a diagrammatic plan corresponding to Fig.v 3; Fig. 5 is a front elevation showing the appearance in a set-up different from that of Fig. 3; Fig. 6 Vis a diagrammatic plan correspondingto Fig. 5; Fig.

7 is an enlargement in front elevation of a detail of Fig. 1; Fig. 8 is a plan of the principal mechanism; Fig. 9 is a side elevation on the line 9-9 applica-` PATENT OFFICE] OfFig. a Fig. 1o is an elevation on the une 10--10 of Fig. 8; Fig. 11 is a rear elevation on the line 11-11l of Fig. 8; Fig. 12 is a front view of the burst representing means, indicating an air burst; Fig. 13 is a view of lthe samemeans, representing an impact burst; Fig'. 14 is a view from the right side of Fig. 12; Vandl Fig. l5 is a View from the-right side of Fig.V 13. "A

Before proceeding to a detailed description of the mechanism it may be explainedthat the apparatus provides a miniature landscape, known as the terrain, on which a miniatureytarget is placed, the landscape being suitably screened and illuminated so as to present to the eye of an ob,- server the appearance of an actual landscape at distances such as `aregused inA artillery ring. Means are provided; above the terrain and'conoealed from the student, for lowering into the students neld of vision a bead, hereafter called a burst bead, the appearance of kwhich realistically imitates that ofthe burst of an artillery lprojectile at the represented distances.' The lowering means. are actuatedv bynan operator so that the burst bead is seen in the students eld of vision and in relation to the miniature target inthe manner that anY actual projectile burst would appear in relation to an actual target.

yReferring nov/'particularly tio-Fig. 1, the apparatus comprises a base 1` to which agscreen 2 is immovably secured. A terrain board 3'A is pivoted to this base near the center or the terrain board, the pivot being concealed; Short sides 4 and a back 5 are rigidly attached to the board 3.,/ Due to 'this pivotingthe terrain board can bek moved, if desired, from Athe straight position shown inrFigs. 1 and 2'to such positions as are shown in Figs. 4 and 6, or others. The screen 2 is of a height to conceal from the student all of the apparatus for lowering the'burst bead 6 into view, and the studentrlooks through an opening 7 practically along the level of the terrain so as to have the Yeiect rof looking at a distant land scape, as shown in, Figs. 3 and 5. The terrain is illuminated by suitable means behind the screen, such Yas electric lights V.8 in the corners of the screen 2 and shielded as at 9 so that the lightV does not shine toward the student. A scale 10 may be conveniently provided on the front of the base 1 to measure the horizontalangle between the axis of the terrain and the axis of the base.` Field artillery observation telescopes and neld glasses'are usually providedwith a mil scale in" the eld of View to measure the lateralideviation of the bursts. This is imitatedin the' present in- Y vention by transparent plates -11, known as reti cules, placed on thelower edge of the opening 7, one for each observer, Figs. 3 and 5. These reticules are marked with mil or other angular scales, such as 12, 13 and 14, Fig. 7, whereby the observer can measure deflections, as explained hereafter. The different sizes of scales are for use at different observer-target distances.

The side walls 4 of the terrain board support parallel horizontal range arms 15 which are graduated bars of about the same length as Vthe terrain board, the bars being just short enough Ato swing with the terrain clear of the screen 2 when the apparatus is positioned as shown in Fig. 4, for example. The side walls 4 are made much shorter than the terrain and areA sloped back 'as shown so that the terrain may be seen from the side through the opening 7 when in such positions as that of Fig. 4. 1t will be seen that the range arms 15 are always iixedsin relation to the terrain. A deflection bar 16 is transversely dis'- posed above the terrain, being carried at either end by shoes 17, 18when resting on the range arms 15. The deflection ybaris graduated, as shown in Fig..8, in mils according Vto the angle subtended at the gun which is the base piece.

Y An indicator assembly 19, which is the `immediate means used in conjunction with the deflection bar representation of bursts, is slidably mounted on the deflection bar. A sheaf block 20, also supported by the deflection bar, may also be placed at any position along thedeflection bar by hooks 21 and clamped thereV as by a set screw 22 or other means. Indicators 2 3, one foreach gunV of the battery represented, Vare disposable along the sheaf` block accordingto the mil scale shown on the block in Fig. 8 to show the spread of bursts due to the deflections of the individual guns. These. indicators 23 are accordingly set in accordance with .the commands for dispersion of fire to indicate the several successive positions of the indicator assembly 19 for-the successive rounds from several supposed guns. s

' Referring now to the details of the apparatus, the range arms are graduated, asbest seen in Fig. 9, either in yards, meters orv otherwise in proportion to the scale of the terrain. The zero point lof the graduations is at a hypothetical gun position well in front of the apparatus. Such a gun position is indicated atv 91', Figs'. 2, 4 and 6. Theshoes 17 and 18, which carry the deiiection barfare to'be set along the range arms at the indicated ranges, each shoe having an index finger such asy 24 which is in .transverse alignment with the basic` position of theburstbead 6.

For the purpose of varying theY position `of the burst bead 6 relatively to thetarget to simulate the dispersion of bursts in actual practiceL due toV probable errors of matriel, tlie'kshoesv 17 and 18. are each made with a convex bottom surface as` indicated at 25 in Fig- 8. Inasmuch as the deflection'bar 16 is formed integrally with or rigidly attached to these shoes, rocking of theshoeswill tilt'the indicator assembly 19 forward and back from the vertical. The forward position is shown in Fig. 1. described hereafter, if the assembly 19 is tilted atthe time, the burst bead .will drop either behind or in front of the, exact range at which it wouldfall on a vertical drop. To prevent the shoes 17 and 18 from sliding along the range arms during rocking, each is provided with a friction surface, this being conveniently accornplished by a at rubber band such as 26 on.4 the shoe, forming in effect a fiat rubber tire. Of course other friction surfaces could be used,

When the burst bead 6 is dropped, as'

A guide-member known as a disperser arm 30 is associated with the shoe 18. This disperser arm 30 is made in the form of a plate disposed along and just outside its respective range arm 15. This plate is pivoted as at 31 to the shoe 18 and has an upstanding ear 32 above the pivot 3l. A tension spring 33 connects the front end of the shoe 18 and the ear 32, tending to pull up the rear end of the disperser arm. The rear end of the arm 30 has a lowered side bracket 34 the rear of'which ends in an upstanding hook 35 turned in to engage the top of the range arm 15. The bracket 34 carries a rotatable element 40, known as a disperser, on a vertical spindle 41. In the preferred form, here shown, this disperser is a cylinder with a notched spiral iiange 42 thereon. An outwardly directed lug 43, Fig. 8, on the rear end of the shoe 18, strikes the flange 42 and so limits the angle between the shoe 18 and the disperser arm 30. The shoes 17 and 18 are always rocked to the rear by the operator, as explained hereafter. The contact of the hook 35 with the top of the range barr15andof .the lug 43 with some point on the flange 42 stop ythis rocking movement. shoe 18 and the disperser larm 30 is set by the point on the spiral 42 at which the lug 43 stops, it follows that the contact between the lug 43 and spiral 42 governs the inclination to which the indicator assembly 19 can be tilted. The spiral 42 is so laid out that its middle point holds the shoe 18 horizontal and consequently holds the indicator assembly 19 vertical. The fall of the burst bead 6 either in front of, or at, or behind the vertical position of the true range depends on the angle of the indicator assembly. The spiral curveof theiiange 42 represents the dispersion of actual bursts in accordance with accepted ballistic tables and its coaction with the lug 34 causes the lphenomenon of dispersion in range to be correctly represented, as will be de- -scribed hereafter. y The indicator assembly 19 is best seen in Figs. 8,

10 and 11. This assembly comprisesa base 50 held to a snug sliding t on the deflection bar 16 by any suitable means such as fa spring leaf 51 whereby the indicator assembly will stayy in any position to which it is set alongthe deflection bar and will not have any rocking motion independent of the bar. The base which is preferably of cast metal construction includes an upright plate 5,2 extending from below and behind thejdeflection bar 16 to a point above and forward of that bar, affording a long firm upwardly inclined base for a diagonally movable plate 55 of generally triangular outline, known as the upper indicator. This upper indicator plate 55 is also preferably a casting from Vthe rear of which theY standard 56 rises. The lower diagonal surface of the upper indicator 55 carriesl an shown in Fig. 10, which is read against the index point indicated by the arrow, and suitable means are provided for clamping the indicator 55 at any given index reading along the base, the preferred means being a slot 100, Fig. 10, in the base 52, parallel to the ydiagonal edge, in which a clamp screw 57 travels. A block 60 slides up and down between the standard` 56 and an upright finger 61. This block is marked with an index, Fig. 10, to read against a scale on-the finger 61. A clamp screw 62 fastens thisblock along thescale. The block includes a bracket 63 at one side from which there depends on a spindle a cylinder 64, called a variator, similar tothel disperser 40 and likewise including a notched spiral flange 65.

The spiral 65 is a mathematicalcurve representing height burst dispersion as given by ballistic tables, therefore a different curve from the .spiral 42, on the disperserdd The -standard 56 .has top and bottom side extensions 66 and 67 :respectively, between which a guide wire 68, parallel to the side of the standard 56, extends, as best seen in Fig. 1l. A collar 70 is movabledown the guide wire 68 by a thumb piece 71,` butk is normally held at the top by a spring 72, the downward motion of; which is guided by an upright finger 73 behind the standard 56. A fork 74 sliding on one edge of the standard 56 keeps the collar 70 i'rom turning around the wire 6b.A Onthe side away from the standard 56 the collar is vertically pierced to receive the upper-end of a wire 75, the lower end of which suspends the burst bead 6. The wire 75 is clamped by a screw 76. This arrangement permits the burst bead 6 to be faced in any direction, and-is necessary toV allow the bead 6 to be faced toward the observer in such ysituations as that of Fig. 4f The bead wire passes downthrough a guide 77 on theV side of the bottom extension 67, and is stopped at the bottom of its motion by a lug 78-on the collar 7D striking the bead is recessed as at 79 and the bottom of the wire 75 is bent to pivot the bead at the side of this recess. `Thus the back of the recess limits the downward position of the bead when suspended in the air as shownin Fig. 14, The bottom and backrof the burst bead are so rounded that whenthe bead is lowered onto the terrain or other object and is no longer freely suspended the weight of the bead and the pressure of the wire 76 downward rocks the burst into the position of Fig. 15.

When the burst beadd hangs freelyY suspended from the wire 75 when viewed at the same level and from the front theV face 80,-the color-of the smoke of an air burst, is visible, as in Fig. 12,

but when the bead rests on some object, the bot.- tom 8l, dark brown, the color-o1 an impact burst, is visible, as in Fig. 13.

Thus when the apparatus is used to represent ringwith projectiles having time. fuzes, or combination time and percussion fuzeswhenl the point of burst is in the air, theburst bead appearance is similar to an actual air burst,-.but when the point of burst is on or below the ground,

the burst bead appears as an actual percussion` burst upon the surface of the ground.

It will of course be appreciated that diie'rent.

beads may be used to represent different appearances. same as the smoke produced bythe burst of actual projectiles which it is intended to simulate, and the face 81 is colored to represent the characteristics of the ground of any particular region as to which it .is desired to give training.A

The appearance of` soil thrown up will of course be somewhat modified by thesmoke of the eX- plosion. In practice the malin distinction of appearance between an air burst and a-graze burst is that the air burst is light coloredand the graze burst much darker.: However, if it is For example, the face is colored thel desired to 'go further .intodetails of color in using thetrain` board, different appropriate beads could be used.

-Consequently one train board-with a suitable assortment of beads canbe used to represent thev ring `of ammunition giving various smoke colors andon various ground. each bead .representingby one. face'the air'b'urst forsome particular explosive and bythe other face the graze burst appearance vdue to soil conditions (or Waterlinthe regionrepresented. j For problems in some kinds of re it is necessary to indicateon the'terrain arbitrary heights to which bursts maybe referred. In actual practice this would be accomplished by setting cross hairs Yon atransitor: other'observing instrument. .For this purpose on the train board one or more stands .85. are provided, each consisting cfa base supporting a vertical wire on which a bead 86 is held by friction at any desired height. This stand. assembly. is known asia Yhigh burst wire. Y* f y In the operation fof the. trainboard, the device shown in Fig. 1 is set 0na table or other suitable support and the student, representing the batteryzcommander, .or otherfoflicer conducting the re, sitsrin a chair. or on a stool, the relativei heights of the train board and of the students eye being such that the student looks just over the reticule 12 thus getting the eiect of a `distant landscape throughv aneld glass as shown in Figs. 3 and 5. The plan of the general set-up for axial re is 'shown in Fig. 2 and variations for other types of nre are shown in Figs. 4 and 6. 'A variety of other arrangements are possible, simulating all the conditions under which eld artillery may fire in target practice or in actual warfare. VFor moving targets, strings problems'wherein" the battery commander is at the battery, the positions 90 and 91 of course coincide- It is Vnot necessary to use a miniature representation of a gun, although this maybe done if desired as a matter of. convenience in visualizing the conditions of the problem. The target 93 is set on-the terrainboard 3, using for the target some objectV of approximately propor- Jcional size in accordance with the assumed range. Burnt match heads make convenient targets. Movable landscape'features on appropriate scale may be placed-on the'terrain `and the target may be placed with respectto these, in a variety ofY combinations such' as would Vbe met with in reality. The distances of the student from the targetand of the gun from the target are measuredV upon the same proportionatescale as the graduations of the range arms 15. Consequently, all distance vrelations are in the? same relative proportionsas would be the case in actuality and all angular relations are the same vas would reallyexist.

To re any problem the student places himself in the appropriate position 90 and 1an' operatb'r of the train 4board stands beside it where he can convenientlyreach `the indicator mechanism 19.

vIn moving target problemsk it is necessary to have va second operator to pull the strings by whiclrthe targets are moved. As an example of the operation, a problem in laterall observation with the gun to the right of the observation post, as shown in Fig. 4, will now be described'. Thev terrain 3 is swung around relatively to the vscreen 2 for the reason that the range bars 15 must always be parallel to the line of fire in order to give a truthful representation. At the same time it is always necessary that the observer look over the reticule 1l in the opening '7. 'Ihe burst bead wire 7 5 is turned so that'the bead 6 will face the student so as to appear to himV as in Figs. 12

and 13.*.

The target 93, Fig."4,. having been placed on the terrain,the appearance rto the observer will be as shown in Fig. 3. This figure makes yit clear why thesides 4 cannot extend too far forward. The distance from the students eye to `the aperture 7 being known, the reticule 11 is set in place with the appropriate scale 12, 13 or 14 uppermost and centered. The student gives the commands for opening fire at an assumed approximate range in accordance with established practice,

indicating the range, deilection,.angle due to assumed diiference in level betweengun and target (known as the angle of site) fuze setting governing the intended height of burst,and any other firing data that would be used in actual firing. The operator lifts the shoes 17 and 18 slightly offthe rangearms 15, and sets them down with the z index 24 at the commanded range, moves the indicator` base 50 on the bar 16 to an arbitrary deflection setting,'sets therblock 60 by its scale according to the angle of site, sets the upper indicator 55 along Yits rscale to represent the given fuze corrector setting. He then rocks the arm 1S forward with his left hand, pressing the arm 34 down with his thumb (against the pull ofthe spring 33) until the hook 35 stops on topof the bar 15. Thus the lug 43 is elevated away from y the flange42, so that the operator can spin the disperser 40 with his right hand. He so spins it and also spins the variator 64. He then rocks the rear end of the shoe ldownward until the lug 43 stops on the ilange 42, in which position the angle of the assembly 19 k(or, more strictly, of the wire 75) is governed by the point along 42 at which 43 rests, and that point, due to the mathematical construction of the flange 42, varies on successive spins according to the variation in distributionofsuccessive rounds in actual firing.

The operator now presses down the thumb piece 71 until it is stopped by the variator 64 or by the burst bead'G striking the terrain 3, as thecase may be, according to where the variator has stopped in its spin. After abouttwo seconds, the length of time the smoke of an actual burst would remain visible, the operator releases the thumb piece and Ythe spring snaps the bead up out of view. Y v The diierent stopping points of the variator between spins give a mathematically accurate variation between heights of successive drops of the bead 6.Vr Consequently the combined eifects of the disperser and variator, imposed uponthe several scale settings cause the bead to represent faithfully the performance of Vreal ammunition, both as to predetermined factors'and as to chance factors. Therefore the student, looking over'the reticule scale at the momentarily visible bead,

makes the same quick estimate of errors inhis ring commands as he would in actual ring, and gives the appropriate corrective commands. The operator makes the corresponding new settings of the train board elements: and again drops the bead. This proceedsuntilthe firing data is cor'- rectly worked out for the given problem, or in other words, until the completion of the Vadjustment of all of the elements of re for each of the guns. Fire for effect may likewise be represented by the train board.

The firing of only one gun has been described above. To represent several guns the sheafblock 20 is used in conjunction with the deection bar 1.6. The sheaf block can be made in any size according to the Anumber of guns the nre of which is to be represented. Fig. 8 illustrates a sheaf block to represent a four gun battery, having one indicator 23 for each gun, movable along the lines marked 1, 2, 3 and 4, corresponding'to the gun members.V The indicators are set along the sheaf block mil scale to indicate the planes of fire of the respective guns, the plane of fire being the plane in which the trajectory of the gun lies. The operator initially sets the indicators 23 arbitrarily for either-diverging, parallel, convergingor cross fire, and represents such nre by setting the indicator assembly 19 to bring the burst bead wire '75 `opposite the indicators successively, in the firing order of the battery, before dropping the bead each time. As commands aregiven which alter the spread of the sheaf, the operator moves the indicators accordingly. It will be understood that the sheaf block is positioned on the deflection bar in the yproper relation which the shear' would bear to the target according to the commands given.

In using the train board to represent high burst transfer problems, Figs. 5 and 6, one reticule is used for each of the two student observers, 91 and 92, and two high burst wires are used to mark the respective lines of observation, Yeach with its bead 86 Vset at the height required above the unseen target. I Each observer looks over the center of his respective reticule at his own bead 86, and observes the successive'appearances of the burst bead 6 as to height and deiiection with respect thereto, just as he would observe actualjhigh burststhrough a transit clamped-at the correspending horizontal and vertical setting. The combined observations are Vused in determining the commands which the operator sets olf on the trainy board elements, all 'in a manner which will be readily understood by artillery officers.

It isapparent from the foregoing examples how iso roo

the principles of operation of this invention may be applied to represent than those described. i v

V It is also apparent that although the invention is particularly shown and described as applied to field artillery training, its features, so far as appropriate, maybe used in the training of other types of artillery.

\ We claim:

other tactical situations 1j In a device for giving instruction lin the conduct of artillery nre, in combination with meansrepresenting a terrain and including a pair of parallel range arms, means mounted on said arms comprising a cross-bar and a shoe having` such rocking motion variable according to ballistic probabilities of range dispersion.`

2'. In a device for giving instruction in the conductl of artillery fire, in combination with means vrepresenting a terrain and including a' pair of parallel range arms, means mounted on said arms comprlsmg a cross-bar, a shoe having a convex atA cross-bar, said shoes having their convex sur-` faces mounted to rock on said arms, respectively, and friction means between said arms and said respective shoes.

3; In a device for giving instruction in the conduct Aof artillery fire, incombination with means representing aterrain and including a pair of parallel range arms, means mounted onsaid arms comprising a cross-bar, a shoel having a convex bottom surface mounted on each end of said cross-bar, said shoes having Ytheir convex sur.

faces -mounted on said arms, respectively, friction means between said arms and said respective shoes, means for rocking said shoes on said arms and means for limiting the amplitude of ,such rocking motion variable according to ballistic probabilities of range dispersion. 'l

4. In a device for giving instruction in the conduct of artillery fire, in combination with means representing a terrain, a cross-bar movably supported adjacent said means, a member slidably mounted upon said cross-bar, `a wire suspended iromsaid member and vertically vreciprocablev with respect thereto, a single bead simulating a plurality Yof appearances of a' projectile burst mounted at the lower end of said wire.

5. In a device for giving instruction in thereonduct of artillery fire, in combination with means representingv a "terrain," a graduated cross-bar movably supported adjacent said means, a slide on said cross-bar, a sheaf-,block'slidablyl mounted on said-cross-bar, a scale on said block,a plu-V ralityfof elements adapted to be positioned upon s'aid'block in` accordance with said scale each to represent a specific piece oia battery, said slide being movable into registrywith any one of said elements, and a single meansv simulating a plurality of appearances of a projectileburst sus' pended from said slide and movableinto close proximity with the terrain. l

6. In a device for giving instruction in the conf* duct'of artillery nre, means representing a terrain, amember movable by an operator relative f to said terrain in response to a students orders,

a single means carried by said member for indir-v cating automatically either fvgraze bursts or air bursts relative to the` terrain,' and' means for governing the movement of said indicating'means in accordance with the proper ratio of air bursts to graze bursts for any given height ofnburst:

setting. Y

7. Ina device for giving instruction in the con` duct of artillery'flre, a bar,4 a slide having a'bifur-J cated baseadapted slidably to receive said bar, a

rod mounted on said slide, a handle member slidable on said rod, a Wire suspended frcm said handle member, and means carried by said wire simulating the appearance of the burst of an artillery projectile, said handle being adapted to move said wire to position said simulating means in given relation to said slide and said rod. l

8. In a device for giving instruction in the conduct ofartillery re, means representing va ter-1 rain, and means associated with said rst-me'n-- tioned means for indicating the longitudinal,V

lateral, and elevational location'with respect tc said terrainof the bursts offprojectiles thrown from a hypothetical piece at any given aim, said last-mentioned means including a single bead simulating the appearance of a projectile burst either in air or on graze.

9. In a device for giving instruction in the conduct or" artillery rire, means representing a terrain,

Y a screen adjacent an edge of said means between said means and the` students' eye, lightslonfthe side of said screen towards-,the terrain-'representing means, means vincludingv said screenl shielding the studentseye from said lights, said screen beingY formed withfa sighting aperture', vand transparent movable means associated with 'said aperture andcarryingindeXes 'adapted to indicate to `the student lateral displacement of objects -on the terrain from his line offsight. le. In a' device for giving instruction inthe conduct of artillery iire, `means representing a terrain, a screen'adjacentv an 'edge of said means between said' means and thestudents eye, said screen beingiormed with a sighting aperture, and a transparent movable plate associatedwith 'said aperture and carrying a plurality of indexes placed on separate parts of the 'edges oisaidplate, each index beingv adapted to indicate to the stu-` dent lateral displacementfrom his line ofV sight of objects on the terrain according to an ass'urriedy observer-target distancev coordinated with lsuch index. l 'f j l1. vIn a device 'forgiving instruction inthe conduct ofartillery fire, means representing a terrain, a screen adjacent an edge ofjsaid means'v betweenisaid means and thestudents eye,'said screen being 'Aformed with a sighting aperture, and transparent movable means associated with said aperture and carrying'ajplurality"ofindeies of different scales adapted toindicat'e'to the student lateral displacement of object'smon' the 4terrain from his line of sight, theiscale ofneach 'index being proportional "to a predetermined vdistance between the ,students eye and said` transparent means. f e l 12. In a device for giving instruction in the'confv duct of artillery remeans representing a terrain, a screen intercepting the students visionoflsa'id means, said screen being formed witha sighting aperture through which r'said means are vvisible in` perspective, `a transparent plate;V mounted" to` slide transverselyvinsaid' aperture, and a plu-' rality ofscales offl angular measurement ,onV said plate, said scales being of' different vsizes but each so proportioned that at a given distance from the students eye to said plate the angle subtended jat conduct of artillery `nre, generally horizontal means representing a terrain and;v revoluble in itsown plane, a memberumovableabpve said plane in to predetermined positions representingv various factors governing thev fallof a projectile in iield artillery hre, saidmernber vhavingamface' of distinctive appearance, means forlovvering said member into approximately-the planeety the terrain, and means for maintaining said member ina position rotated vabout equal amountbut opposite direction to the rotation 'of' said,Y terrainrepresenting means. :4;V l

14. In a device for givinginstruction in' the'- conduct of artillery hre, in combination'Y with means representing 4a terrain, a cross-.barmovably supported adjacent said means, almembe'rv slidably mounted upon said cross-bar, an element simulating theburst ofIa'projeetile suspended from said member andvertically rreciprocable with' respectV thereto, said element being "adapted to be moved into predetermined proximity with the terrain, and means to limit the length of movement of said element, said element being approximately the shape of half an elongated drop having ua, longitudinal flat face and a rounded back and an enlarged rounded lower end.

15. In a device for giving instructionin the v,a ,vertical pivot -in rio conduct of artillery fire, a bead representing the appearance oifa projectile burst under varying conditions, said bead being approximately the shape of half an elongated drop having a longitundinalflat face and a rounded back and an enlargedirounded lower end, said ilat face being surfaced to simulate theappearanee of an lair burst, said rounded end being surfaced to simulate the appearance of a graze burst, a suspension wire carrying said bead, and a hinge connection ofI said bead upon said wire, saidl hinge including stop means to hold saidbeadsuspended with its iiat face inclined nearly tothe vertical, but allowing said back to rest flat on the terrainrepresenting means when not suspended.

1 6.` I n a device for giving instruction in the conduct ofartillery nre, a bead representing the appearance of a-` projectile burst, under lvarying conditions, a suspension wire carryingsaidbead, said beadV having aV flat face andV anenlarged rounded-lower end, andra hinge connection between said bead and said wire whereby saidjiat face is exposed to view when the bead is suspended and said lower endlis exposed toview when the beadis spportedzfrom below.

VA1'1."In"combinai'liori, in-.an apparatus for giving instruction thecenductof artilleryre, a singlev b'ad havi'rlgtw eiposable faces one of Awhich is colored asfai air burstfand the other of which is clor''d" a'sa graz'e'burst'andlmeans for4 exposing the 'st cmed'facewln thebead'is in the air Y fr- 'eipomsingy the secondV named 'f ace when said" bd' 'cnes"into .contact with aA material oect? M. Y, i., l v e "`I8I'In a' devicefor giving instruction in the conduct of artillery nre, a bead adapted to repr'sntjtn appearance of! a pfojectuejburst' in aino'iri'grazaa reprsentaition ofa terrain, a :[ifanvvrkM'above said4 terraim a screenl hiding sdrrnework butlpermitting a view ofthe terrain, nreafnsorV suppi'tifi'g said'xbead freni said framework," and" a* parigini @mimetica with sdsupprting Ieans", said spring'normally holdsaidflead, concealedu by d scneer'i.

I nf a'devic `f givingv instruction in the conduct"ofatillery`nre,"acrss barmounted lon a^ pair'of convexfdclie shoes,v a slide having a bifurcated basen "and having a portion offset" from saidba adaptedfslidabl'y to receive said bar, a rd vmouriteron"the offset portion of said slide, 'a'.fliandle niemberfslidable on said rod, awire suspendedv from sidfhandle member andin a `plial'xe`"ra`dial tsaidfroclier shoes, and means carried liyhsaid4 4wire 'simulating nthe appearance of lthe'bust of an'art'illery'projectile, said handle b 'engadaptedt -movl-i5said wireto position said simulating -meas in Vgiven relation to said slide antisera red; i k2ilx`n-afildviee for giving instruction in the conduct'bf y`artillery".fire, combination with "means repesntn'ga `'terrain and gincludingV a pircf parallel range arms, means mounted on said'l ar'mscomprising across-b'arand a shoe having corivei:A ibottom surface mounted on ehved" of i said crs-bar, said shoes having dei: conveicfsurface's lslidably Ymounted on said arms, respectively, means for rocking said shoes on said arms,` a stop comprising a surfacel formed to a` probability curve of dispersion in range, and an element movable with one of saidshoes adapted to contact with said stop. Y

2l. In a device for giving instruction in the conduct of artillery iire, in combination with means representingY a lterrain and including a pair vof parallel range4 arms, means mounted on said arms comprising a cross-bar anda Ashoe having a convex bottom surface mounted on each end of said cross-bar, said shoes having their convex surfaces slidably mounted on said arms, respectively, means for-rocking said shoes on said arms, ak stopvcomprising a surface formed to a probabilityl curve ofl dispersion in range, and formedon a cylinder, said cylinder'being pivoted forlfree rotation, and anelement movable with one ofnsaid shoes yadapted to contact with said stop. Y

212,. In a devicefor giving instruction in the conductjofI artillery iire,` means representing a terrainj, and means associated with said firstmentionedmeans for indicating the longitudinal, lateral, and elevational location with respect to said terrain ofthe burst of projectiles thrown from a hypothetical piece at any given aim, said last-mentionedmeans including a bead simulating the appearance of a projectile burst, means for-moving( said bead intoa position in proximity to said terrain tov simulate the explosion of a projectile and mechanical means for controlling saidrpositionV of said bead in mathematical accordance with ballistic` probabilities of dispersion in range and inrheight of burst.

23,.v In a device for giving instruction in the conduct of artillery fire, a cross-bar mounted on a pair of convex rocker shoes, a slide having a bifurcated base and having a portion offset from said bar adaptedslidably to receive said bar, a

plate perpendicular to said cross-bar and slidably mountedk on an upwardly and forwardlyinclined element of said offset portion, an index means forplacing said plate in relation to said inclined element tov represent a fuze corrector setting, meansl for holding said plate and said element in xedrelative position, an upright member mounted on said plate, and `means carried by said upright member'comprising a suspension movable in a" generally vertical direction, and an elementen the lower end of said suspension for simulating `the appearance of v'the burst of an artillery projectile;Y

24. In a device for givinginstruction in the conduct of artillery re, means representing a terrain, a member movable by an operator relative to -said terrain in response to a students orders, a single bead carried by said vmember for indicating selectively either graze bursts or air bursts `relative Ato the terrain, a variable stop for governing the movement of said bead, the variations of said Vstop being representative of ballistic variation probabilities in height of burst, a supportv carrying said stop, said support` being vertically movable to positionsrepresenting selected angles of site, and means for maintaining said support at any selected representative position.

STEPHEN Y. MCGIFFERT.

HUGH P. ADAMS.

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